Creating lifelike digital representations of creatures with hair poses difficult problems in the field of computer graphics. (Herein, we use the term "hair" broadly, so as to encompass hair, fur, and the like.) Achieving a high degree of visual realism demands that the computer-generated image reflect lifelike deviations and imperfections with respect to characteristics including shape, texture, texture, color, lighting, separation, and curvature, all at the granular level of individual hairs. However, because a typical image literally involves millions of individual hairs, it has in the past seemed impractical from a computational standpoint to apply this degree of high fidelity computer graphics modeling to hair. The prior art in this field has therefore generally failed to provide tools that realistically model, animate, and render hair with attention to the appearance and characteristics of individual hairs. Such prior art approaches are generally unsatisfactory for important applications where high fidelity is critical, such as providing computer graphics special effects for motion pictures.
A further, related challenge is the need to integrate hair elements with other scene elements in a consistent manner. For example, hair elements created through the use of computer graphics techniques should exhibit characteristics such as motion blur and shadowing to the same extent that other objects in the scene do. Otherwise, image realism can be compromised.
The failure of prior art techniques to take individual hair characteristics into account, and to integrate hair properly with other scene elements, has typically resulted in special effects which are all too obvious to motion picture viewers, and therefore unconvincing. A computer graphics methodology for modeling, animating and rendering hair images in a manner that is both highly realistic as well as computationally practical is therefore needed. More broadly, such a methodology could prove equally valuable in analogous computer graphics applications, wherever it is desired to represent images made up of a relatively high density of individual image elements having both common and independent image characteristics.